AAlliibbaabbaa CClloouudd Alibaba Cloud DDaatata TTraannssmmissisiosni oSner vSiceervice BeBset Psrta Pctricaecstices Document Version: 20210927 Document Version: 20210927 Dat a Transmission Service Best Pract ices·Legal disclaimer Legal disclaimer Alibaba Cloud reminds you t o carefully read and fully underst and t he t erms and condit ions of t his legal disclaimer before you read or use t his document . If you have read or used t his document , it shall be deemed as your t ot al accept ance of t his legal disclaimer. 1. You shall download and obt ain t his document from t he Alibaba Cloud websit e or ot her Alibaba Cloud- aut horized channels, and use t his document for your own legal business act ivit ies only. The cont ent of t his document is considered confident ial informat ion of Alibaba Cloud. You shall st rict ly abide by t he confident ialit y obligat ions. 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Please direct ly cont act Alibaba Cloud for any errors of t his document . > Document Version: 20210927 I Best Pract ices·Document convent io Dat a Transmission Service ns Document conventions St yle Descript ion Example A danger notice indicates a situation that Danger: Danger will cause major system changes, faults, Resetting will result in the loss of user physical injuries, and other adverse configuration data. results. Warning: A warning notice indicates a situation Warning that may cause major system changes, Restarting will cause business faults, physical injuries, and other adverse interruption. About 10 minutes are results. required to restart an instance. A caution notice indicates warning Not ice: Not ice information, supplementary instructions, If the weight is set to 0, the server no and other content that the user must longer receives new requests. understand. A note indicates supplemental Not e: Not e instructions, best practices, tips, and You can use Ctrl + A to select all files. other content. Closing angle brackets are used to Click Set t ings > Net work> Set net work > indicate a multi-level menu cascade. t ype. Bold formatting is used for buttons , Bold menus, page names, and other UI Click OK. elements. Run the cd /d C:/window command to Courier font Courier font is used for commands enter the Windows system folder. Italic formatting is used for parameters bae log list --instanceid Italic and variables. Instance_ID This format is used for an optional value, [] or [a|b] ipconfig [-all|-t] where only one item can be selected. This format is used for a required value, {} or {a|b} switch {active|stand} where only one item can be selected. > Document Version: 20210927 I Dat a Transmission Service Best Pract ices·Table of Cont ent s Table of Contents 1.Switch workloads to the destination database 05 2.Use triggers and functions to implement incremental DDL migra…tion for0 9PostgreSQL databases 3.Disable slow query log to improve migration performance 13 4.Change the character set of an ApsaraDB RDS for MySQL instan…ce 14 5.Configure a data synchronization task for a source database th…at conta2i2ns a trigger 6.Migrate data between databases that have different names 25 7.Set a cache update policy by using the change tracking feature… 26 > Document Version: 20210927 I Best Pract ices·Swit ch workloads t o Dat a Transmission Service t he dest inat ion dat abase 1.Switch workloads to the destination database This topic describes how to switch your workloads to the destination database and prepare a rollback solution. This allows you to minimize the negative impact of data migration on your business. Prerequisites A data migration task is configured and it is in the Migrat ing or Complet ed state. For more information, see Overview of data migration scenarios. Precautions We recommend that you switch workloads to the destination database during off-peak hours to minimize the negative impact. Before you switch workloads to the destination database, you must stop writing data to the source database and suspend the business. We recommend that you create and authorize a database account for data migration. This allows you to distinguish session information and improve data security. Procedure 1. Wait until the task progress bar shows Increment al Dat a Migrat ion and T he migrat ion t ask is not delayed or a delay time of less than 5 seconds. Not e If you do not select Increment al Dat a Migrat ion when you configure the data migration task, the task progress bar does not show Increment al Dat a Migrat ion. After data is migrated, the migration task automatically ends. In this case, you must suspend the business and stop writing data to the source database before you run the data migration task. Skip to Step 5 and proceed. 2. Suspend the business and stop writing data to the source database. 3. Log on to the source database and run the following statements based on the database type to view session information. Make sure that no new sessions are used for write operations. Not e You can view the processes or sessions between DTS and the source database by running the preceding statements. MySQL SQL Server Oracle PostgreSQL Redis MongoDB show processlist; select * from sys.dm_exec_connections; select sid,serial#,username,program,machine,status from v$session; > Document Version: 20210927 5 Best Pract ices·Swit ch workloads t o Dat a Transmission Service t he dest inat ion dat abase select * from pg_stat_activity; CLIENT LIST use admin db.runCommand({currentOp: 1, $all:[{"active" : true}]}) 4. After the status of increment al dat a migrat ion changes to T he migrat ion t ask is not delayed, wait for 1 minute or longer, and then manually stop the migration task.